Fear of needles is a very common form of phobia. The seizures you mention are most likely a panic reaction you experience in response to the needle itself or even possibly the idea of needles. So yes, your sensations are a kind of anxiety brought about by a change in your arousal state. Phobias are usually very uncomfortable and sometimes debilitating.

Fortunately the treatments for phobia are well grounded in research and clinical practice. I've included a link for you to read more about phobia prevention and treatment. Many people simply live with their phobia because they are relatively unobtrusive. If however this fear is getting in the way of your life, or you just want rid of it, my suggestion is to get hold of a licenced psychologist in your area. Many psychologists specialise in the treatment of phobia so you shouldn't have too much difficulty finding one.